Such pocket plates are inserts for a mold side wall ring that are used to mold information onto a tire sidewall, for example, tire brand information or a bar code for inventory identification. A mold side wall ring may be used over a relatively long period of time, and for molding different versions of a single tire model. The removable plates are changed when the information on the plate needs to be changed for different tire molding requirements.
In some conventional molds, pocket plates are held in place in a mold by magnets, by screws fastened from the front of the plate, or by screws fastening the plates from the back of the side wall ring. In the case of magnets, when the mold is heated, the side wall ring and plate expand, which provides friction to help hold the plate in place.
The conventional means of holding pocket plates in side wall rings present drawbacks. In molds in which the plates are fastened with front attaching screws, the screw heads leave a mark on the molded tire. When the screws are fastened from the back of the plate, the mold must be first removed from the press to gain access to the screws. Once the plate is changed, the mold must be reinstalled and realigned in the press, which involves time and effort. The magnet fastened plates must be allowed to cool before they can be removed, which causes delay, and additionally are difficult to grasp for removal because of the lack of an edge or grip on the surface of the plate.
Another conventional device removes pocket plates from a mold. A mold half may have a recess to receive a pocket plate. A rod may be inserted in a hole in a mold half part. A first end of the rod may be disposed at an accessible outer surface of the mold half part. A second end of the rod may be disposed in a position adjacent to the pocket plate recess. The rod may be movable in the hole and include a cam surface that may be selectably moved into the recess to push on the pocket plate by movement of the rod.
The conventional rod may be rotatable in the hole and the cam surface may be radially arranged on the rod for movement upon rotation. In addition, the second end may include a hook radially opposite the cam surface for engaging a catch on the back surface of the pocket plate to secure the pocket plate in the recess. The conventional rod may alternatively be slidable in the hole with the cam being linearly arranged on the second end of the rod. The rod may include a tab for engaging a slot in the pocket plate to selectably secure the pocket plate in the recess.